Polishing rouge



PHILIP J'. HESS, OF KOKOMO, INDIANA, ASSIGNOR TO PITTSBURGH PLATE GLASS COMPANY, A CORPORATION OF PENNSYLVANIA.

POLISHING ROUGE.

No Drawing.

T 0 all whom it may concern:

Be it known that I, PrrILIP J. HESS, a citizen of the United'St'ates, and a resident of Kokomo, in'thecounty of Howard and State of Indiana, have made a new and useful Invention in Polishin Rouges, of which the following is a specification.

The invention relates to polishing rouge and mixtures thereof. The rouge is intended primarily for use in polishing plate glass, and the invention has for its primary objects the provision of a rouge which will permit of the more rapid polishing of the glass, which can be applied to the polishing machines throughout substantially the entire polishing'period, and which will not mass or build up upon the polishing felts. A further object is the provision of a rouge which can be made more quickly and economically than has heretofore been done.

In my process, as well as in those heretofore practiced for the production of rouge for polishing purposes, ferrous sulphate, commonly known as copperas, is employed. The symbol for this material when in crystaline form is Fe SO,,.7H O. The sugar form has also been very extensively employed, in which case the combined water is less.

The method of burning the copperas heretofore has varied considerably. In some cases it was customary for the operators to charge the furnace before quitting at night, leaving a low temperature in the furnace, while others would charge in the morning with a comparatively warm furnace, from 600 to 900 F., the temperature being gradually/raised and finally reaching 1600 t6 1700F. The charge was stirred at about thirty minute intervals and the total period of burning was about ten hours. During the burning. the water of crystallization was driven fromvthe copperas and the sulphate converted for the most part into ferric oxide or rouge. B12 0 with the formation also of a variable percentage of basic ferric sulphate. 2Fe 0 -5SO A variable percentage of the ferrous sulphate FeS( also generally remained unconverted. As illustrative of the proportions of the Application filed October 30, 1919. Serial No. 334,656.

above compounds produced by one characteristic calcining operation is the follow- 6 0 65 t 85% 2Fe O,5SO 10 to 30% FeSO 1 to 5% In some cases this mixture was washed with water, thus eliminating the soluble basic ferric sulphate and the ferrous sulphate, and leaving only the ferric oxide. In

order to use the oxide thus produced, in

polishing, it was necessary to mix it with water and add a solution containing ferrous sulphate (ordinarily referred to as acid), such solution being secured by passing steam or water through a mass of copperas.

The addition of the solution of sulphate was necessary in order to secure a proper polishing action by the rouge, the function of the solution of sulphate being to maintain the plasticity or stickiness of the rou e. The amount of acid in the mixture was etermined by a hydrometer. Care was taken to avoid any excess of the copperas solution because of its tendency to crystallize upon the polishing blocks and cause a marrlng mixture contained as its acid content a substantial amount of the ferrous sulphate.

(FeSO,) solution, such acid content in the first instance being practically all ferrous sulphate solution and in the second case being made up partly of the sulphate solution and partly of the basic ferric sulphate solution.

I have found that the basic ferric sulphate is much more effective in its action as a component of the rouge polishing mixture than the ferroussulphate. Both compounds tend to give the mixture the necessary stickiness or plasticity to make it effective as a polisher, but-the basic ferric sulphate gives greater friction and hence more polishing effect, and will not crystallize till the concentration is very great.

The copperas solution, on the other hand, begins to crystallize "ery readily on concentration and such crystallization tends to form a crust at the edge of the polishing blocks and produce sleaking or marring ofthe polished surface of the glass. The tendency of the mixture to mass or build up on the felts is much less with the basic ferric sulphate than with the copperas solution. My process is therefore directed to the production of mixture in which the acid solution is substantially all provided by the use of the basic ferric sulphate, and in which the ferrous sulphate is reduced to a minimum.

In the practiceof my invention the crys talline form of copperas is preferably employed, although the sugar form may be used. This copperas is calcined in a'difi'erent manner from that heretofore described for the old process, the time of heating being reduced to about four hours and the temperatures employed being relatively much higher. The purpose of this method of calcining or burning is to produce a product which contains a smaller proportion of the ferrous sulphate and a much higher proportion of the basic ferric sulphate. The calcining at a higher temperature and for a shorter period of time produces this result, a characteristic table of proportions being as follows:

Fe O n' 65 to 75% Qlt e O Z5SO a 25 to 35% F8804 I In the use of this material no copperas water is added, the basic ferric sulphate taking the place of the copperas solution of the old process, so that all that is necessary in the use of this material is to add the necessary amount of water, the mixture being prefe'rably much thicker thanthat employed With the material produced by the old process. The basic ferric sulphate which goes into solution acts to maintain the plasticity of the mixture and give it stickiness when used in the polishing operation. and the tendency of the mixture to mass or build up on the felts is reduced to a minimum, so that the'rnixture can be used throughout almost the entire polishing, operation. About one pound of the polishing compound per four; and a half gallons (4. of water'has been found to give the best results when the mixture is applied according to my system, but this amount may be varied within certain master limits depending on the method of use Without departing from the invention; A larger amount of rouge is applied during the first part of the operation than during the concluding portion, but the use of the felts with water alone continues for only a few minutes at the start of the operation. lVith this mixture the total period of the polishing, operation as compared with the operation using the ordinary rouge mixture heretofore described isreduced about 30%, a substantial saving also being effected as to power, rouge and felt, although the power required per unit of time is greater than in the old operation, due to the greater friction produced by the use of the basic ferric sulphate.

In the calcining operation of my process the FeSO is reduced to a minimum, which is desirable since its tendency is to crystallize as heretofore referred to and thus produce marks or sleaks on the surface of the glass. The use of the basic ferric sulphate to produce the necessary plasticity and stickiness avoids this difliculty when used in the right proportion. I have found that. the proportion above indicated produces the best results although a somewhat lower as well as somewhat highen proportion may be employed. When the proportion of basic ferric sulphate becomes too high, the sulphate may act as a lubricant and thus retard polishing, and when the amount is too low the friction and consequently the polishing effect decreases a The rouge'as produced by my process appears to be somewhat softer than that pro duced by the old processes, which may have something to do with the better results secured in polishing, but as heretofore stated,

I believe that the advantage is primarily due to the action of the basicferric sulphate in maintaining the plasticity or stickiness of the rouge throughout the polishing operation,-whereby the tendency of the material to thicken up or build up and to crystallize, is avoided. The material is preferably produced by careful regulation of the temperatures, so that the basic ferric sulphate and the ferric oxide are produced at the same time and in the right proportions from a body of copperas, but my invention is not limited to this-method of producing the compound containing the ingredients necessary to produce the desired results For instance, the copperas maybe so burned as to produce substantially only ferric oxide and this ferric oxide mixed with the proper proportion of basic ferric sulphate produced in some other way. Basic. ferric sulphate may be produced in various ways, one of which is the long continued burning of copperas at a relatively low temperature.

The reactions involved in carrying out my calcining operation are believed to be about;

occurring more or less concurrently:

If the heat were continued'long enough I the basic ferric sulphate would be converted into ferric oxide, but the heat is applied, as heretofore stated, so as to get the proper proportions .of the oxide and sulphate. A small proportion.of the FeSQ (about two tenths per cent) remains unde'composed, as heretofore indicated in the table showing the proportions of the compounds after calcmlng.

In burning the copperas, the oven is first brought to high temperature, 1600 to 17 00 F and the copperas is then charged. The temperature then falls, due to the cooling effect of the charge, to about 900 to 1000 F'., and the heating continues, the temperature reaching 1600 F. within two and one half hours. From thistime on the temperature is raised to 1700 to 1800 F. The whole calcining operation requires about' four hours and the charge is stirred or worked about three times during the entire calcination.

\Vhile the foregoing constitutes the preferred'method of operation, I have found that substantially the same results may be obtained if the furnace is maintained at a. somewhat higher temperature, in which case, however, the time of burning should decreased. By increasing the temperaturethe time of calcining may be reduced the neighborhood of three hours. The time of burning may also run somewhat over four hours if the temperatures are employed below those stated. The time is also somewhat dependent upon the size ofthe charge, the character of the furnace, and other conditions, so that the invention is not limited to the precise periods or temperatures specified heretofore- What "I claim is: w

1. A ouge polishing COIIIPOllIld (EOIHPItS- ing upwards of twenty per cent baslc fBI'IlC' sulphate and substantially all of the remainder ferric oxide.

2. A rouge polishing compound comprising between twenty to forty per cent basic ferric sulphate,-and substantially all of the remainder ferric oxide.

3-. A rouge polishing compound comprising approximately one third basic ferric sulphate and two thirds ferric oxide- 4. A rouge polishing compound comprising'between twenty to forty per cent basic ferric sulphate, a trace of ferrous sulphate, and the remainder ferric oxide.

5. A rouge polishing compound comprising water, basic ferric sulphate in solution therein, ferric oxide, and atrace only of ferrous sulphate.

6. Afrouge polishing mixtureconsisting of water and of a. polishing compound comprising approximately one third basic ferric sulphate and two thirds ferric. oxide, the compound being mixed withthe water in the approximate proportions of one pound of compound per four and one-half gallons of water.

7. A rouge polishing mixture consisting of water and a polishing compound, comprising approximately one-third basic ferric sulphate and two-thirds ferric oxide, the compound being mixed with the water in the approximate proportions of 3.7 to 5.3 gallons of water per pound of compound.

8. A rouge po ishing mixture consisting of water and a polishing compound comprising from twenty to forty per cent of basic ferricsulphate and substantially all of the remainder ferric oxide, the compound being mixed with. the water in the approximate" proportions of one pound of the compound per four and'one-half gallons of Water.

9. A'rouge polishing mixture consisting of water and a polishing compound comprising "from twenty to forty per-"cent. of basic ferric sulphate and substantially all of the remainder ferric oxide, the compound being mixed with the water in the approximate A proportions of 3.7 to 5.3 gallons of water per pound of compound.

In testimony whereof, I have hereunto subscribed my name this 23rd day of October, 1919;

. PHILIP J. HESS. 

